In high-density server installations, physical space is at a premium. A calculation of total costs includes, dedicated server room construction costs, climate control costs, and maintenance costs for the entire facility. Allocation of these costs, across all the electronic equipment in the facility, determines operating costs per square inch.
Another calculation is the Data Center Infrastructure Efficiency (DCIE). Calculation of the DCIE comes from dividing the amount of power used by all the electronic equipment by the total amount of power used by the facility. A higher DCIE percentage indicates a more cost-efficient facility.
Energy-efficiency is a key concern. A general rule is, the cost of cooling the equipment is approximately 50% of the cost of operating the equipment. The Transaction Processing Performance Council (TPC) publishes performance benchmarks, which are useful for the evaluation of server installations.
The key financial calculation for a data center is the electricity cost of the total computing capability. This same metric is as useful for massive data centers as it is for installations that are more modest.
To make efficient use of physical space all installations use as a standard the 42U server rack mounted in a 42U server rack cabinet.
These are either stand-alone units or units deployed side-by-side in the thousands. Stand-alone units benefit from having cooling systems and soundproofing so they do not require a specialized dedicated server room. When used in multiple units, the cost efficiency increases as the size of the facility increases.
As reported by Data Center Knowledge, the trend for new server farms built to support cloud services is for the facilities to be super-sized. For example, Microsoft is building a huge new data center in Des Moines, Iowa of 1.2 million square feet. Equinix is building a facility of 1.16 million square feet in Ashburn, Virginia and SuperNAP in Las Vegas is expanding to 1.3 million square feet. These investments are in the billions of dollars.
For most companies making investments that are more modest, the 42U server rack is still the standard because it has been widely accepted in the industry. It is compatible with computer technology, music equipment components, telephone equipment, and other electronic equipment designed to fit in a rack, which is 19 inches wide.
In all these industries, the height of the electronic modules has the standard of being multiples of 1.752 inches, which is a single rack unit (U). The rack unit standard established in 1934, had slight modification once in 1992 (changed from 1.75 inches to a more accurate 1.752 inches).
The technology and equipment have continued to change with progress, but the rack unit standard is here to stay. Some equipment takes up more than one rack unit, but always in multiples of rack units. A 42U rack server has space for 73.584 inches of equipment height.
An example of a typical single rack installation is all the computer equipment needed for a small business:
- 5 desktop computers
- 5 dual-process servers
- 1 RAID
- 2 Switches
- 1 Firewall
- 1 UPS
All this equipment fits nicely in one 42U server rack cabinet. Whether the need is for a single stand-alone server cabinet or for tens of thousands, the industry standard for space savings and efficiency is the 42U rack server and cabinet.